Improving the Lung Delivery of Nasally Administered Aerosols During Noninvasive Ventilation—An Application of Enhanced Condensational Growth (ECG)

Longest, P. Worth; Tian, Geng; Hindle, Michael

doi:10.1089/jamp.2010.0849

Cited by 56 publications

(71 citation statements)

References 60 publications

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“…Longest and colleagues [33][34][35][36][37][38][39][40][41][42][43][44][45][46] have been exploring approaches to generate submicron particles, which are less likely to impact in the circuit, but grow large enough in the respiratory tract that they are likely to be deposited in the lungs. This work is preclinical, but has potential for benefit if adapted to clinical use.…”

Section: Approaches To Improve Aerosol Delivery During Hfncmentioning

confidence: 99%

Aerosol Therapy During Noninvasive Ventilation or High-Flow Nasal Cannula

Hess

2015

Respir Care

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Noninvasive ventilation (NIV) and high-flow nasal cannula (HFNC) are increasingly used for patients with acute respiratory failure. Some patients receiving these therapies might also benefit from inhaled drug delivery. Thus, it is attractive to combine aerosol therapy with NIV or HFNC. The purpose of this paper is to review the available evidence related to the use of inhaled aerosols with NIV or HFNC. Available evidence supports the delivery of aerosols during NIV. Inhaled bronchodilator response might be improved with the use of NIV in acute asthma, but the evidence is not sufficiently mature to recommend this as standard therapy. Evidence does support aerosol delivery without discontinuation of NIV. Clinical studies on aerosol delivery during HFNC are needed, and based on the available in vitro evidence, it is not possible to make a recommendation for or against aerosol delivery during HFNC.

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Section: Approaches To Improve Aerosol Delivery During Hfncmentioning

confidence: 99%

Aerosol Therapy During Noninvasive Ventilation or High-Flow Nasal Cannula

Hess

2015

Respir Care

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“…For both of these studies, delivery rates to the lung are expected to be significantly lower than the fraction exiting the cannula interface due to deposition in the nasal airways. (13)(14)(15) Depositional losses in nasal cannulas at higher flow rates consistent with NPPV and HFT for adults and for different particle sizes have previously not been reported. The administration of pharmaceutical aerosols during other forms of NIV was previously reviewed (8)(9)(10)16) and indicated typical patient delivery rates of less than 1-10% from in vitro studies and 1-6% under in vivo conditions.…”

mentioning

confidence: 94%

“…Condensational growth then occurs when the aerosol and humidity streams combine in the nasopharynx and continue downstream. In the study of Longest et al, (15) both in vitro results and CFD predictions indicated that, with ECG delivery, depositional losses in the NMT region were approximately 15% at a total flow rate of 30 L/min through the model, and condensational growth increased the initially submicrometer aerosol size to approximately 2 lm in the trachea. In comparison, deposition of a conventional 4.7-lm aerosol in the NMT geometry was found to be approximately 70% under identical flow conditions.…”

mentioning

confidence: 97%

“…The administration of pharmaceutical aerosols during other forms of NIV was previously reviewed (8)(9)(10)16) and indicated typical patient delivery rates of less than 1-10% from in vitro studies and 1-6% under in vivo conditions. Longest et al (15) recently proposed the concept of enhanced condensational growth (ECG) (17,18) to improve the lung delivery of nasally administered aerosols during HFT. Aerosol deposition and size increase were evaluated in an adult nose-mouth-throat (NMT) replica geometry using both in vitro experiments and computational fluid dynamics (CFD) simulations.…”

mentioning

confidence: 99%

“…Size increase of the aerosol may be further enhanced with the use of hygroscopic growth excipients. (20)(21)(22) One limitation of the nasal delivery study by Longest et al (15) was the use of an unrealistic nasal cannula interface that was only intended to route the aerosol to the nostrils in the experiments. Therefore, depositional losses in realistic or practical nasal cannulas were not considered.…”

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confidence: 99%

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High-Efficiency Generation and Delivery of Aerosols Through Nasal Cannula During Noninvasive Ventilation

Longest

Walenga

Son

et al. 2013

Journal of Aerosol Medicine and Pulmonary Drug Delivery

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Background: Previous studies have demonstrated the delivery of pharmaceutical aerosols through nasal cannula and the feasibility of enhanced condensational growth (ECG) with a nasal interface. The objectives of this study were to develop a device for generating submicrometer aerosols with minimal depositional loss in the formation process and to improve aerosol delivery efficiencies through nasal cannulas. Methods: A combination of in vitro experiments and computational fluid dynamics (CFD) simulations that used the strengths of each method was applied. Aerosols were formed using a conventional mesh nebulizer, mixed with ventilation gas, and heated to produce submicrometer sizes. An improved version of the mixer and heater unit was developed based on CFD simulations, and performance was verified with experiments. Aerosol delivery was considered through a commercial large-bore adult cannula, a divided (D) design for use with ECG, and a divided and streamlined (DS) design. Results: The improved mixer design reduced the total deposition fraction (DF) of drug within the mixer by a factor of 3 compared with an initial version, had a total DF of approximately 10%, and produced submicrometer aerosols at flow rates of 10 and 15 L/min. Compared with the commercial and D designs for submicrometer aerosols, the DS cannula reduced depositional losses by a factor of 2-3 and retained only approximately 5% or less of the nebulized dose at all flow rates considered. For conventional-sized aerosols (3.9 and 4.7 lm), the DS device provided delivery efficiencies of approximately 80% and above at flow rates of 2-15 L/min. Conclusions: Submicrometer aerosols can be formed using a conventional mesh nebulizer and delivered through a nasal cannula with total delivery efficiencies of 80-90%. Streamlining the nasal cannula significantly improved the delivery efficiency of both submicrometer and micrometer aerosols; however, use of submicrometer particles with ECG delivery resulted in overall lower depositional losses.

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Dynamic growth and deposition of hygroscopic aerosols in the nasal airway of a 5‐year‐old child

Kim

Xiuhua

2012

Numer Methods Biomed Eng

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Hygroscopic growth within the human respiratory tract can be significant, which may notably alter the behavior and fate of the inhaled aerosols. The objective of this study is to evaluate the hygroscopic effects upon the transport and deposition of nasally inhaled fine-regime aerosols in children. A physiologically realistic nasal-laryngeal airway model was developed based on magnetic resonance imaging of a 5-year-old boy. Temperature and relative humidity field were simulated using the low Reynolds number k - ε turbulence model and chemical specie transport model under a spectrum of four thermo-humidity conditions. Particle growth and transport were simulated using a well validated Lagrangian tracking model coupled with a user-defined hygroscopic growth module. The subsequent aerosol depositions for the four inhalation scenarios were evaluated on a multiscale basis such as total, subregional, and cellular-level depositions. Results of this study show that a supersaturated humid environment is possible in the nasal turbinate region and can lead to significant condensation growth (d / d(0) > 10) of nasally inhaled aerosols. Depositions in the nasal airway can also be greatly enhanced by condensation growth with appropriate inhalation temperature and humidity. For subsaturated and mild inhalation conditions, the hygroscopic effects were found to be nonsignificant for total depositions, while exerting a large impact upon localized depositions.

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Improving the Lung Delivery of Nasally Administered Aerosols During Noninvasive Ventilation—An Application of Enhanced Condensational Growth (ECG)

Cited by 56 publications

References 60 publications

Aerosol Therapy During Noninvasive Ventilation or High-Flow Nasal Cannula

Aerosol Therapy During Noninvasive Ventilation or High-Flow Nasal Cannula

High-Efficiency Generation and Delivery of Aerosols Through Nasal Cannula During Noninvasive Ventilation

Dynamic growth and deposition of hygroscopic aerosols in the nasal airway of a 5‐year‐old child

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